Thin film composite (TFC) membranes including ultra-thin active layers and porous supports have been widely used in reverse osmosis (RO) or nanofiltration (NF) processes for desalination. The active layer in a TFC membrane controls separation properties, while the support layer enhances mechanical strength.
The crosslinked aromatic polyamide produced by interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) has been a successful commercial product. Although the crosslinked aromatic polyamide TFC membranes show very high salt rejection (≧99%) and reasonable water flux (20˜55 LMH), the membranes are not sufficiently effective in filtering out harmful toxins such as arsenic and boron, and they also can be sensitive to chemical disinfectants such as chlorine. Chemical attack by disinfectants ultimately results in membrane failure as measured by enhanced passage of both salt and water.